How can 2 PSUs be so different?

[Li'l ol' me]

I'm trying to build a silent-ish PC so I've got meself a QTEC 350W (the low
noise <27db version).

The PSU I've been using with no problems is a stock 350W that came with the
case (not sure of the make as I've just put it back in upside down!).

I put in the QTec PSU and to be on the safe side I took out EVERYTHING from
my Abit NF7-S (v1.1) bar my XP2100 (t'bred), the globalwin cooler (on lowest
setting about 2700RPM), 2x256mb PC3200 and my Radeon 8500 (AGP).

When I switched on, it seemed to post, but I only got as far as the memory
count and the PC freezes. Can't even get into BIOS. Tried connecting my
IBM deskstar 60gb HD up as it froze just before the point it would normally
start IDing IDEs, but I couldn't post at all. After disconnecting the HD, I
STILL couldn't post at all, but when I left it overnight I found I was back
to square one (freezing on POST screen).

So I plopped my stock PSU back in and everythings totally normal. The
annoying thing is that I have a second case with the same PSU but only 300w,
and that copes with all the socket As I can throw at it (as long as there
not dead to begin with). On the smaller PSU I can just make out LC-B300ATX
(I guess that makes the larger one LC-B350ATX).

The other funny thing about the QTec PSU is that it has a monitor pass-thru,
like it can even cope with just a XP2100 and cooler! I might try this on a
P3 system to see if that copes.

And just to rub it in, it sounded no quieter anyway, although the globalwin
drowns out everything even at 2700 RPM.

I can't afford any other low-noise solution (I got this VERY cheap).

Any ideas?

 

[philo]

Any ideas?

i think you;ve already mentioned it

 

[Guest]

I put in the QTec PSU and to be on the safe side I took out EVERYTHING
from my Abit NF7-S (v1.1) bar my XP2100 (t'bred), the globalwin cooler
(on lowest setting about 2700RPM), 2x256mb PC3200 and my Radeon 8500 (AGP).

When I switched on, it seemed to post, but I only got as far as the
memory count and the PC freezes.

So I plopped my stock PSU back in and everythings totally normal.
The annoying thing is that I have a second case with the same PSU
but only 300w, and that copes with all the socket As I can throw
at it (as long as there not dead to begin with). On the smaller
PSU I can just make out LC-B300ATX (I guess that makes the larger
one LC-B350ATX).

Either your QTec is a defective sample, or QTec managed to produce
power supplies of even worse quality than Deer (LC- means L&C, a Deer
brand).

 

[PC]

Your problem may well have solved mine though.

I've been running a Duron 750 system quite happily for some time with
the occasional freezng hard drive.

Put in Athlon 1200C and had the same result you did.
Tried XP2200, sameagain.

Swapped motherboards for later model, same again with both Athlon
CPUs.

That leaves the only common item to be the PSU. Others on this group
have told me that the tiny increase in voltage for the cPU makes a
world of difference to the output needed from the PSU.

Wish me luck with a better PSU.

Cheers,

PC

 

[Ed Light]

Try RMA'ing it for a replacement. Could be a bad one.

 

[Ed Light]

Others on this group
have told me that the tiny increase in voltage for the cPU makes a
world of difference to the output needed from the PSU.

It's more the amperage draw. The faster cpu's just happen to have a
different voltage. The more speed, the more amps they draw, and the voltage
times the amps = the watts consumed.